Abstract:In this study, we proposed an innovative oxidation-absorption method for low-temperature denitrification (160-240 • C), in which NO is initially catalytically oxidized by hydrogen peroxide (H 2 O 2 ) vapor over titania-based catalysts, and the oxidation products are then absorbed by NaOH solution. The effects of flue gas temperature, molar H 2 O 2 /NO ratio, gas hourly space velocity (GHSV), and Fe substitution amounts of Fe/TiO 2 catalysts on the denitrification efficiency were investigated by a well-designed experiment. The results indicated that the Fe/TiO 2 catalyst exhibited a combination of remarkable activity and deep oxidation ability (NO converted into harmless NO 3 − ). In order to comprehend the functional mechanism of the Fe dopant's local environment in TiO 2 support, the promotional effect of the calcination temperature of Fe/TiO 2 on the denitration performance was also studied. A tentative synergetic mechanism could be interpreted from two aspects: (1) Fe 3+ as a substitute of Ti 4+ , leading to the formation of enriched oxygen vacancies at the surface, could significantly improve the adsorption efficiency of •OH; (2) the isolated surface Fe ion holds a strong adsorption affinity for NO, such that the adsorbed NO could be easily oxidized by the pre-formed •OH. This process offers a promising alternative for current denitrification technology.

To realize efficient recycling of lithium manganese oxide (LMO) from spent Liion batteries, microwave-assisted deep-eutectic solvent (DES) treatment is proposed. The effects of the DES, temperature, time, and liquid/solid (L/S) ratio on the leaching efficiency were studied by orthogonal and single-factor experiments. The results of the orthogonal experiments indicated that the effects of each factor on the leaching of Li and Mn ions lay in the following order: DES > L/S ratio > temperature > time. The results of the single-factor experiments indicated that the leaching efficiencies of both Li and Mn ions reached 96% under the condition of choline chloride-oxalic acid (ChCl-OA), 15 min, 75°C, and L/S ratio of 6 g/0.1 g. Microwave-assisted DES treatment is highly efficient for recycling LMO from Li-ion batteries, greatly decreasing the leaching time from several days to less than 1 h even at 75°C in comparison with the traditional heating method.

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